Typically, a polarizing plate is used in a liquid crystal display panel. This polarizing plate needs to be affixed to an appropriate position on a substrate constituting the liquid crystal display panel.
According to PTL 1, a set of two slits, or cutout patterns, is formed at each of four corners of a black matrix outside a display portion. In addition, according to PTL 1, it can be determined that the polarizing plate is affixed at an appropriate position when only one of the slits in each set is covered by the polarizing plate, and it can be determined that the polarizing plate is not affixed at an appropriate position when both of the two slits in each set are covered by the polarizing plate or when neither of the slits in each set is covered by the polarizing plate.
According to PTL 2, alignment marks are provided at two diagonal corners of a rectangular polarizing plate. When a polarizing plate constituting a liquid crystal display panel is to be affixed to a substrate, alignment marks for positioning are displayed within a display portion, and the polarizing plate is affixed so that the positions of the displayed alignment marks match the positions of the alignment marks provided on the polarizing plate. According to PTL 2, this configuration makes it possible to match the position and the orientation of the polarizing plate in the liquid crystal panel with high accuracy.